In general, refrigerators are home appliances for storing foods at a low temperature in an inner storage space covered by a door. Since such a refrigerator cools the inner storage space by using cool air, foods stored in the storage space may be stored in a refrigerated or frozen state.
Also, an ice maker for making ice may be provided inside a typical refrigerator. The ice maker is configured so that water supplied from a water supply source or a water tank is received into an ice tray to make ice. Also, the ice maker is configured to separate the made ice from the ice tray in a heating or twisting manner.
As described above, the ice maker, in which water is automatically supplied and ice is automatically separated, may have a structure which is opened upward to draw the made ice up. Also, each of the ice pieces made in the ice maker having the above-described structure may have a shape having at least one flat surface such as a crescent moon shape or a cubic shape.
If an ice has a spherical shape, the ice may be more convenient in use and, also, provide unusual feeling to a user. Also, when the made ice pieces are stored, a contact area between the ice pieces may be reduced to reduce the likelihood of the ice pieces being stuck together.
When an ice maker makes spherical ice, the upper portion of a tray should be closed during the ice making process. However, an open structure is required to separate the spherical ice. Thus, an upper tray and a lower tray should be separately provided. A pressing type ice maker in which water is collected in a lower tray and an upper tray is pressed facilitates the supplying of water, but requires a vertical elevation movement of the lower tray to prevent water from leaking to the outside during a pressing process. Also, rotation of the lower tray is required to prevent ice pieces from staying in the lower tray without dropping down from the upper tray to an ice bank during an ice separating process. That is, in the case of the pressing type ice maker, since an operation structure in which the lower tray combines a straight line motion with a rotational motion, the ice maker may be complicated in structure.